The Education Ministry mooted closing two single-sex high schools and moving Christchurch Girls' High School to the Christchurch Boys' High School site as part of its education overhaul in the region.

However, the ministry says no options have been considered and it is waiting on geotechnical information on school sites.

The ministry's business case, released on Friday, shows how it reached proposals to close 12 schools and put 26 through some form of merger.

The document reveals the ministry mooted closing Avonside Girls' High School and Shirley Boys' High School, and having Christchurch Girls' High School site-share on the Christchurch Boys' High School grounds.

The move would have reduced the provision for 2500 pupils and meant the city would not have had a single-sex secondary school on its own site.

At present, the four schools cater for just under 5000 pupils.

A ministry spokesman confirmed the options were developed but said "no options have yet been considered".

"In accordance with the Government business case framework, as wide a range of options as possible was mooted.

"There has been no discussion or consideration of any options for single-sex secondary provision."

On September 13, when the Government's plans for Christchurch schools were announced, a document released to schools and media showed the ministry proposed merging Shirley at Christchurch Boys's High and Avonside at Christchurch Girls' High.

However, the ministry quickly backtracked, saying there were no firm proposals to merge or close the schools.

This month, Education Minister Hekia Parata said she was prepared to "categorically rule out" a merger of the secondary schools.

She then released a statement, saying she "has never received proposals for mergers".

The schools have yet to receive any correspondence from the ministry to say that the mergers are off the cards.

Avonside Girls' High board of trustees chairman Tim Bergin said the school knew "only what was in the media".

Shirley Boys' High principal John Laurenson said the school was waiting on the geotechnical report, which would shape its future.

"Nobody is talking to me, despite requests for information," he said.

"If it [the geotechnical information] is positive, the proposal, I guess, will be to rebuild on site. But if it is negative, we will be looking at other proposals."